Coincubation of human spermatozoa with Chlamydia trachomatis in vitro causes increased tyrosine phosphorylation of sperm proteins

Elementary bodies (EBs) of the obligate intracellular bacterium Chlamydia t rachomatis are responsible for the first step of attachment to host cells. We have studied the effects of EBs on human sperm protein tyrosine phosphor ylation, which is important to sperm function. Indirect immunofluorescence using antiphosphotyrosine antibodies show-ed that serovar E, but not LGV, c aused increased tyrosine phosphorylation which was localized to the sperm t ail region. Immunoblotting revealed that serovar E caused a marked increase in tyrosine phosphorylation of 80- and 95-kDa sperm proteins, whereas sero var LGV caused increased phosphorylation of only the 80-kDa moiety. Conside ring the importance of tyrosine phosphorylation for sperm capacitation and other aspects of sperm function, we conclude that EBs may affect these even ts.